In the known food or beverage machines, in particular for home use, there are scaling issues due to the deposit of minerals contained in the mixing fluid used for the food or beverage preparation. Typically, minerals such as calcium build up in the fluid pipe system of the machine and possible to its other functional components which are in contact with said mineralized fluid, such as the fluid pump, or the fluid heater, eventually leading to blockage of the machine. More precisely, deposits of minerals on the contact surface of the fluid conducting elements of the machine occurs predominantly in the portions of said fluid conducting elements wherein said fluid is subject to thermal changes or turbulent flows in particular at sudden conduit diameter changes.
In existing solutions, descaling of the pipe system of the machine is performed by using chemicals. However, this is disadvantageous because it requires purchase of an extra item by the consumer. Moreover, it is mildly hazardous and therefore requires that the machine be flushed several times after use to purge the system of the chemicals. This chemical descaling process requires frequent and repeated applications, and requires the consumer to remember and organise to perform these descaling cycles as appropriate. Moreover, if the consumer forgets about descaling, the machine will inevitable block after some time, and may become impossible to repair. This undue burden on the consumer is not very user-friendly, hence undesirable.
Alternatively to the known chemical descaling technique to be performed by the user, another possibility exists to descale the machine fluid pipe system, which is the mechanical technique. In this case, a mechanical element is forced through at least some portions of the fluid pipe system, for instance the fluid injection needle which injects the fluid within the ingredient capsule. Alternatively to the manual operation, the mechanical descaling of some portions of the fluid pipe system can be performed in an automatic manner, when the machine is operated. Such an automated mechanical descaling is described for instance in the applicants European patent publication EP 2460449 A1. However, although such a technique has certain advantages, it adds extra complexity to the machine and thus injects extra potential for failure into the product, as well as adding extra cost on the machine, which makes the same machine more expensive to purchase for the consumer.
Having regard to the existing machines and descaling techniques which are discussed above, it appears that there is a need for a beverage preparation machine that requires little operation by the consumer to perform a descaling process, while being simple and inexpensive to the manufacture, and requires little or no maintenance.